RRF 3.4b3 - bed heater fault

[SIam]

@cadetc Welcome in the club https://forum.duet3d.com/topic/24809/3-4-0-beta-3-heater-0-fault/2

[Phaedrux]

Can you give us some details about the bed and heater?

[CadetC]

@phaedrux said in RRF 3.4b3 - bed heater fault:

Can you give us some details about the bed and heater?

Bed is made out of 8 mm aluminum plate with dimensions 340X340
Heating element - 300X300 - 220V, 750W Kenovo connected via SSR

Starting with RRF 3.2 I had all versions installed, including betas - it was only with RRF3.4b3 that this problem occurred

my bed config from config.g

M308 S0 P"temp0" Y"thermistor" T100000 B4138 A"Bed"      ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out0" T0                                   ; create bed heater output on out0 and map it to sensor 0
M307 H0 B0 S1.00                                     ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0                                              ; map heated bed to heater 0
M143 H0 S130                                         ; set temperature limit for heater 0 to 130C

[dc42]

@cadetc @SIam in order to help ne work on a solution, please can each of you do the following:

1. Heat the bed to the same temperature that you tuned it at (resetting heater faults as necessary);
2. When the temperature is stable, use command M573 P0 (assuming it is heater 0) to monitor the heater PWM;
3. When the value reported by M573 is stable, report in this thread:

• The M573 result
• The ambient temperature at the time
• The bed temperature that you tuned at and set
• The heater tuning results, or the resulting M307 command.

[SIam]

@dc42 Here we go, The first thing is M573 is never stable, the heat bed is on Temp since 3 hours

28.8.2021, 13:27:28	M573 P0
Average heater 0 PWM: 0.238
28.8.2021, 13:27:27	M573 P0
Average heater 0 PWM: 0.247
28.8.2021, 13:27:26	M573 P0
Average heater 0 PWM: 0.177
28.8.2021, 13:27:24	M573 P0
Average heater 0 PWM: 0.215
28.8.2021, 13:27:23	M573 P0
Average heater 0 PWM: 0.267
28.8.2021, 13:27:22	M573 P0
Average heater 0 PWM: 0.262
28.8.2021, 13:27:20	M573 P0
Average heater 0 PWM: 0.216
28.8.2021, 13:27:19	M573 P0
Average heater 0 PWM: 0.228
28.8.2021, 13:27:18	M573 P0
Average heater 0 PWM: 0.214
28.8.2021, 13:27:16	M573 P0
Average heater 0 PWM: 0.184
28.8.2021, 13:27:14	M573 P0
Average heater 0 PWM: 0.262
28.8.2021, 13:27:11	M573 P0
Average heater 0 PWM: 0.199
28.8.2021, 13:27:09	M573 P0
Average heater 0 PWM: 0.262
28.8.2021, 13:27:07	M573 P0
Average heater 0 PWM: 0.289
28.8.2021, 13:27:06	M573 P0
Average heater 0 PWM: 0.185
28.8.2021, 13:27:03	M573 P0
Average heater 0 PWM: 0.278
28.8.2021, 13:27:02	M573 P0
Average heater 0 PWM: 0.236
28.8.2021, 13:27:00	M573 P0
Average heater 0 PWM: 0.209
28.8.2021, 13:26:58	M573 P0
Average heater 0 PWM: 0.244
28.8.2021, 13:26:56	M573 P0
Average heater 0 PWM: 0.147

The ambient temperature is 17 C°

The Bed temperature that i have Tuned was 100C° and set to 75C°

and at last the tuning result is

M307 H0 R0.466 C285.252:285.252 D0.89 S1.00 V24.3 B0 I0

if you need more tests, let me know

[dc42]

@siam thanks. If the M573 reading is not stable, is the temperature oscillating a little? If so, increase the M307 D parameter until it is stable. You can do this while the heater is hot.

[CadetC]

@dc42 said in RRF 3.4b3 - bed heater fault:

@siam thanks. If the M573 reading is not stable, is the temperature oscillating a little? If so, increase the M307 D parameter until it is stable. You can do this while the heater is hot.

the temperature after reaching the desired 110 degrees is a little unstable, it fluctuates within +0.3, -0.3 degrees
I tried to change parameter D, but I don't know by what values I can change it - I changed it by 0.1 to the value 4.80 with no visible improvement.
Here are the readings taken about an hour after setting the bed temperature

M573 results

.08.2021, 16:03:22	m573 P0
Average heater 0 PWM: 0.196
28.08.2021, 16:03:16	m573 P0
Average heater 0 PWM: 0.165
28.08.2021, 16:03:15	m573 P0
Average heater 0 PWM: 0.163
28.08.2021, 16:03:14	m573 P0
Average heater 0 PWM: 0.178
28.08.2021, 16:03:12	m573 P0
Average heater 0 PWM: 0.213
28.08.2021, 16:02:57	m573 P0
Average heater 0 PWM: 0.256

Ambient temperature 20C
Bed temperature 110C

M307 H0

8.08.2021, 16:00:46	M307 H0
Heater 0 model: heating rate 0.858, cooling time constant 275.9, dead time 4.18, max PWM 1.00, calibration voltage 24.0, mode PID
Computed PID parameters:
 setpoint change: P49.8, I1.466, D145.6, load change: P49.8, I3.664, D145.6

[SIam]

@dc42 The temperature is a bit unstable 69.8 C° - 70.2C° I have increased the d Value by 0.1 up to 6 without any improvement

[dc42]

@siam @CadetC you can double or treble the D parameter if necessary, although that will only help if you are getting regular temperature oscillations.

[SIam]

@dc42 I can do what I want, the PWM Value is always unstable, the only change I can see is that the temperature fluctuations get bigger when I increase the D value. I have now the D value increased by 0.5 until D=25

[SIam]

I have now written a quick and dirty macro to get the values and share the results

var D_Value = 1
var D_Value_max = 10
var D_value_incr = 0.5
var get_pwm_repeat = 10
var count_pwm = 0
echo >"PWM.log" " " ; write new file to sys:
while var.D_Value < var.D_Value_max
	echo >>"PWM.log" " "
	echo "D_Value " ^ var.D_Value
	echo >>"PWM.log" "D_Value " ^ var.D_Value
	M307 H0 R0.466 C285.252:285.252 D{ var.D_Value } S1.00 V24.3 B0 I0  ; change that line to fit to your heater settings
	echo "M307 H0 R0.466 C285.252:285.252 D" ^ var.D_Value ^ " S1.00 V24.3 B0 I0" ; change that line to fit to your heater settings
	echo >>"PWM.log" "M307 H0 R0.466 C285.252:285.252 D" ^ var.D_Value ^ " S1.00 V24.3 B0 I0" ; change that line to fit to your heater settings
	set var.D_Value = var.D_Value + var.D_value_incr
	G4 S2
	while var.count_pwm < var.get_pwm_repeat
		M573 P0
		echo "PWM: " ^ heat.heaters[0].avgPwm
		echo >>"PWM.log" "PWM: " ^ heat.heaters[0].avgPwm
		G4 S1
		set var.count_pwm = var.count_pwm +1
	set var.count_pwm = 0

The result

 
 
D_Value 1
M307 H0 R0.466 C285.252:285.252 D1 S1.00 V24.3 B0 I0
PWM: 0.196
PWM: 0.235
PWM: 0.239
PWM: 0.199
PWM: 0.179
PWM: 0.201
PWM: 0.220
PWM: 0.186
PWM: 0.156
PWM: 0.154
 
D_Value 1.5
M307 H0 R0.466 C285.252:285.252 D1.5 S1.00 V24.3 B0 I0
PWM: 0.224
PWM: 0.215
PWM: 0.257
PWM: 0.303
PWM: 0.278
PWM: 0.215
PWM: 0.181
PWM: 0.195
PWM: 0.243
PWM: 0.282
 
D_Value 2.0
M307 H0 R0.466 C285.252:285.252 D2.0 S1.00 V24.3 B0 I0
PWM: 0.206
PWM: 0.225
PWM: 0.268
PWM: 0.285
PWM: 0.264
PWM: 0.263
PWM: 0.302
PWM: 0.342
PWM: 0.336
PWM: 0.321
 
D_Value 2.5
M307 H0 R0.466 C285.252:285.252 D2.5 S1.00 V24.3 B0 I0
PWM: 0.246
PWM: 0.203
PWM: 0.198
PWM: 0.200
PWM: 0.167
PWM: 0.138
PWM: 0.141
PWM: 0.172
PWM: 0.185
PWM: 0.159
 
D_Value 3.0
M307 H0 R0.466 C285.252:285.252 D3.0 S1.00 V24.3 B0 I0
PWM: 0.206
PWM: 0.255
PWM: 0.264
PWM: 0.228
PWM: 0.191
PWM: 0.195
PWM: 0.234
PWM: 0.257
PWM: 0.255
PWM: 0.255
 
D_Value 3.5
M307 H0 R0.466 C285.252:285.252 D3.5 S1.00 V24.3 B0 I0
PWM: 0.199
PWM: 0.218
PWM: 0.219
PWM: 0.204
PWM: 0.206
PWM: 0.235
PWM: 0.259
PWM: 0.247
PWM: 0.233
PWM: 0.251
 
D_Value 4.0
M307 H0 R0.466 C285.252:285.252 D4.0 S1.00 V24.3 B0 I0
PWM: 0.296
PWM: 0.299
PWM: 0.336
PWM: 0.361
PWM: 0.329
PWM: 0.269
PWM: 0.233
PWM: 0.241
PWM: 0.239
PWM: 0.197
 
D_Value 4.5
M307 H0 R0.466 C285.252:285.252 D4.5 S1.00 V24.3 B0 I0
PWM: 0.191
PWM: 0.170
PWM: 0.140
PWM: 0.130
PWM: 0.151
PWM: 0.149
PWM: 0.123
PWM: 0.100
PWM: 0.095
PWM: 0.117
 
D_Value 5.0
M307 H0 R0.466 C285.252:285.252 D5.0 S1.00 V24.3 B0 I0
PWM: 0.218
PWM: 0.209
PWM: 0.194
PWM: 0.207
PWM: 0.223
PWM: 0.201
PWM: 0.165
PWM: 0.152
PWM: 0.169
PWM: 0.204
 
D_Value 5.5
M307 H0 R0.466 C285.252:285.252 D5.5 S1.00 V24.3 B0 I0
PWM: 0.175
PWM: 0.165
PWM: 0.155
PWM: 0.131
PWM: 0.107
PWM: 0.101
PWM: 0.126
PWM: 0.165
PWM: 0.205
PWM: 0.242
 
D_Value 6.0
M307 H0 R0.466 C285.252:285.252 D6.0 S1.00 V24.3 B0 I0
PWM: 0.299
PWM: 0.304
PWM: 0.327
PWM: 0.317
PWM: 0.284
PWM: 0.246
PWM: 0.218
PWM: 0.216
PWM: 0.226
PWM: 0.215
 
D_Value 6.5
M307 H0 R0.466 C285.252:285.252 D6.5 S1.00 V24.3 B0 I0
PWM: 0.233
PWM: 0.248
PWM: 0.233
PWM: 0.222
PWM: 0.242
PWM: 0.269
PWM: 0.266
PWM: 0.248
PWM: 0.251
PWM: 0.275
 
D_Value 7.0
M307 H0 R0.466 C285.252:285.252 D7.0 S1.00 V24.3 B0 I0
PWM: 0.240
PWM: 0.253
PWM: 0.258
PWM: 0.235
PWM: 0.207
PWM: 0.190
PWM: 0.169
PWM: 0.149
PWM: 0.161
PWM: 0.194
 
D_Value 7.5
M307 H0 R0.466 C285.252:285.252 D7.5 S1.00 V24.3 B0 I0
PWM: 0.174
PWM: 0.145
PWM: 0.144
PWM: 0.170
PWM: 0.191
PWM: 0.178
PWM: 0.154
PWM: 0.155
PWM: 0.177
PWM: 0.190
 
D_Value 8.0
M307 H0 R0.466 C285.252:285.252 D8.0 S1.00 V24.3 B0 I0
PWM: 0.194
PWM: 0.214
PWM: 0.201
PWM: 0.167
PWM: 0.141
PWM: 0.147
PWM: 0.177
PWM: 0.211
PWM: 0.223
PWM: 0.207
 
D_Value 8.5
M307 H0 R0.466 C285.252:285.252 D8.5 S1.00 V24.3 B0 I0
PWM: 0.217
PWM: 0.201
PWM: 0.168
PWM: 0.148
PWM: 0.152
PWM: 0.146
PWM: 0.121
PWM: 0.101
PWM: 0.112
PWM: 0.116
 
D_Value 9.0
M307 H0 R0.466 C285.252:285.252 D9.0 S1.00 V24.3 B0 I0
PWM: 0.112
PWM: 0.132
PWM: 0.125
PWM: 0.118
PWM: 0.135
PWM: 0.159
PWM: 0.162
PWM: 0.141
PWM: 0.134
PWM: 0.155
 
D_Value 9.5
M307 H0 R0.466 C285.252:285.252 D9.5 S1.00 V24.3 B0 I0
PWM: 0.150
PWM: 0.167
PWM: 0.193
PWM: 0.196
PWM: 0.180
PWM: 0.186
PWM: 0.215
PWM: 0.248
PWM: 0.276
PWM: 0.291

[CadetC]

@dc42
Today I checked again how this issue looks like - when heating up to 110C I had to delete fault once, then everything was OK.
After about 30 minutes temperature quite stable, small fluctuations +0.1, -0.1 degrees .
After the temperature of the table stabilized (with small deviations as above) the result of M573 varied from 0.226 to 0.242 - I checked it for about 15 minutes

30.08.2021, 17:18:38	M307 H0
Heater 0 model: heating rate 0.858, cooling time constant 275.9, dead time 4.18, max PWM 1.00, calibration voltage 24.0, mode PID
Computed PID parameters: setpoint change: P49.8, I1.466, D145.6, load change: P49.8, I3.664, D145.6
30.08.2021, 17:17:49	M573 p0undefined

[hestiahuang]

@cadetc said in RRF 3.4b3 - bed heater fault:

ad to delete fault once, then everything was OK.
After about 30 minutes temperature quite stable, small fl

Refer to https://forum.duet3d.com/topic/24809/3-4-0-beta-3-heater-0-fault/12