Siemens 420 manual Analog output DAC, Signal output through the DAC channel

3 Functions Issue 07/04

3.6.4Analog output (DAC)

Number:		1
Parameter range:		r0770 – P0781
Function chart number:		FP2300
Features:
-	cycle time:	4 ms
-	resolution:	10 bit
- accuracy:		1 % referred to 20 mA

Setpoints, actual values and control signals inside the drive inverter are read-out via the D/A converter using these analog input. The digital signal is converted into an analog signal. All of the signals can be output via the D/A which contain the "CO" abbreviation in the parameter text (refer to list of all of the BICO parameters in the parameter list). Parameter P0771 defines, by assigning the parameter number, the quantity which is output as analog signal through the DAC channel (refer to Fig. 3-27). The smoothed output frequency is output, e.g. via the analog output, if P0771 = 21.

r0020 CO: Freq. setpoint before RFG

r0021 CO: Act. filtered frequency

r0024 CO: Act. filtered output freq.

r0025 CO: Act. filtered output voltage

r0026 CO: Act. filtered DC-link volt.

r0027 CO: Act. filtered output current

...

r0052 CO/BO: Act. status word 1

r0053 CO/BO: Act. status word 2

r0054 CO/BO: Act. control word 1

...

			D/A conv.	D	KL
Function	rxxxx	P0771			D/A conv.+
			channel
				A	KL
					D/A conv.−

0 ... 20 mA

Fig. 3-27 Signal output through the DAC channel

In order to adapt the signal, the DAC channel has several function units (filter, scaling, dead zone) which can be used to modify the digital signal before conversion (refer to Fig. 3-28).

			P0777	P0778	P0779	P0780			r0774
		P0773					P0781
				DAC			DAC	D	KL	mA
Function	rxxxx	P0771							DAC+ KL	... 20
				scaling			dead zone	A
									DAC−
										0
Fig. 3-28	DAC channel

NOTE

The analog output only provides the current output (0 ... 20 mA). A 0 ... 10 V voltage signal can be generated by connecting a 500 Ohm resistor across the output.

MICROMASTER 420	Operating Instructions
94	6SE6400-5AA00-0BP0