Lakeshore Learning Materials 647 - Manual (Page 39)

Lake Shore Model 647 Magnet Power Supply User’s Manual
Remote Operation 4-9
4.2.1 Serial Interface Hardware Configuration
Below is a technical description of the 6224 option card for the Serial Interface configuration. (Note: See
Appendix C for Serial Interface on CMP.) Table 4.2 defines communication parameters. Terminators are fixed
to Carriage Return (CR) and Line Feed (LF).
The serial interface connector is a standard 6-wire RJ-11 (telephone) jack. Lake Shore offers the Model 2001
10-foot Cable Assembly, Model 2002 RJ-11 to DB-25 Adapter, and the Model 2003 RJ-11 to DE-9 Adapter.
See Chapter 4 – Service for Serial I/O connector and adapter pin out details, and Chapter 5 – Options and
Accessories for adapter dimensions.
Table 4-2 Serial Interface Specifications
Transmission: Three-Wire Bits per Character: 1 Start, 8 Data, and 1 Stop
Baud Rate: 300, 1200 or 9600 Timing Format: Asynchronous
Parity Type: None Connector: Two RJ-11 Modular Socket
Fixed Terminator: CR (0DH) LF (0AH) Transmission Mode: Half Duplex
Data Interface Levels: Transmits & Receives Using EIA Voltage Levels
4.2.2 Serial Interface Settings
To use the Serial Interface, set the Baud rate. See Paragraph 4.1.1.
4.2.3 Sample BASIC Serial Interface Program
The QuickBASIC V4.0 program in Table 4.3 is a sample interactive serial poll routine for the MPS Serial
Interface. Below are typical examples using this BASIC program. (User input is in bold type.)
ENTER COMMAND? *IDN?
Identification Query. Returns manufacturer, model
number, 0, and Firmware Date.
LSCI,622,0,120193
ENTER COMMAND? ISET 25;IOUT?
Output Current Setting and Query. Instructs unit to set
current to 25 amps and then asks for current reading.
+24.9975A
ENTER COMMAND? OVP?
Overvoltage (Quench) Protection Circuit Status Query.
Unit returns setting, where 0 = Off and 1 = On.
0
ENTER COMMAND? RI?
Remote Inhibit Status Query. Unit returns setting, where 0
= Inactive and 1 = Active.
0
ENTER COMMAND? MODE?
Mode Status Query. Instrument returns mode, where 0 =
Local, 1 = Remote, or 2 = Remote with Lockout.
1
4.2.4 Notes On Using The Serial Interface
• To chain commands together, insert a semi-colon (;) between them. Multiple queries cannot be chained.
• Queries use the same syntax as the associated setting command followed by a question mark (?). They
usually return the same information that is sent.
• Add a query to the end of a command string if the controller must return information. For example, RMP
0;RMP? commands the MPS to pause the ramp then return the ramp status to confirm the change.
• The MPS returns nothing queries without a “?" and ignores misspelled commands and queries.
• The term "free field" indicates a floating decimal point that can be placed at any appropriate place in the
string of digits.
• Leading zeros and zeros following a decimal point are unneeded in a command string, but they are sent in
response to a query. A leading “+” is not required, but a leading “–” is required.
• [term] indicates where the user places terminating characters or where they appear on a returning
character string from the MPS.