Lakeshore Learning Materials 622 - Manual (Page 79)

Lake Shore Model 620/622/623/647 Magnet Power Supply User’s Manual
Options & Accessories 6-11
3. The selected current multiplied by the heater resistance (e = i × r) must be less than 15 Vdc for the MPS
to accurately determine compliance of the switch heater (open resistance).
Examples: A 100 ohm heater resistance set for 100 mA yields 10 volt compliance (Ohm's Law). This is
greater than the required 0.75 Vdc and yet less than 15 Vdc. This allows proper performance. A 10 ohm
heater resistance set for 50 mA yields 0.5 Vdc – less than the minimium for acceptable operation. The MPS
cannot reliably determine the switch status and may report erroneously in some conditions. The best solution
is to raise the current to 100 mA or greater while meeting all conditions.
6.3.5 Model 6228 Remote Operation Commands
IPSH Program PSH Current
Input: IPSH [current] where [current] = a value from 0 to 125 mA
Remarks: The initial condition is 0 mA. Current can be set from 0 to 125 mA but will actually be set in
4 mA increments.
IPSH? PSH Current Query
Input: IPSH?
Returned: A number between 0 and 125.
Remarks: Returns three characters plus up to two terminators.
PSH Program PSH Heater Status
Input: PSH [status] where [status] = 0 to turn off the persistent switch heater, or 1 to turn on the
persistent switch heater. Heater ON means persistence is OFF.
PSH? PSH Heater Status Query
Input: PSH?
Returned: 0 if the heater is OFF, or 1 if the heater is ON. If a current setting of 0 is entered, the value
returned is 0. Heater ON means persistence is OFF.
Remarks: Returns one character plus up to two terminators.
PSHC? PSH Compliance Status Query
Input: PSHC?
Returned: 0 if PSH output is under the output compliance limit, or 1 if the output is over the limit.
Remarks: Returns one character plus up to two terminators.
PSHIS? Current Setting When PSH Was Turned Off
Input: PSHIS?
Returned: The value returned is a number between ±125.0000 A.
Remarks: Returns nine characters plus up to two terminators.