Baud Rate, Data Bits/Parity Bits/Stop Bits

Baud Rate

B_2.4

B_2.4, B_4.8, B_9.6, B_19.2, B_38.4, B_57.6, B_125, B_250, B_500

The baud rate is given in kbaud. For example, B_9.6 corresponds to a 9600 baud. Note: There is no equivalent RS232/485 command.

Data Bits/Parity Bits/Stop Bits

P8n1

8n1, 8n2, 7n2, 7E1, 7E2, 7o1, 7o2, 701, 702, 711,712

The first character, “8” corresponds to the number of data bits. (e.g. 7 or 8).

Second character, “n” corresponds to the parity bit. (e.g. n- no parity, E- even parity, o- odd parity, 0- space, 1- mark)

The last character, “1” corresponds to the number of stop bits. (e.g. 1 or 2) Note: There is no equivalent RS232/485 command.

Turnaround Delay

dt06

dt00, dt01, ...dtFE, dtFF

The turnaround delay is unique to multipoint communications. It is the delay between receipt of an incoming command to transmission of the response. Each increase in the hex value corresponds to an increase in the delay time of approximately 8 ms.

*{aa}T={dd}<CR>

Decimation Ratio

dr5F

5F, 6F, …, FF

The decimation ratio can be used to set the amount of sampling which is performed by the HPM-2002- OBE’s A/D converters. The higher the value of the hex number, the more sampling takes place before the pressure reading is updated. More sampling leads to more stability of pressure readings particularly below 1 mTorr. However, the increased sampling increases the response time of the gauge to sudden pressure changes.

D={dddd}<CR>

Save EEPROM

S_EE

Save EEPROM stores the calibration parameters which are in the HPM-2002-OBE’s CPU into the HPM- 2002-OBE’s CPU board’s EEPROM. The CPU board’s EEPROM is not the HPM-2002s tube EEPROM. The CPU board EEPROM stores the gauge setup (baud rate, parity, address, set points, gas selection, etc.). The HPM-2002s tube EEPROM stores the tube’s calibration parameters.

EEW<CR>

Restore EEPROM

r_EE

Restore EEPROM transfers the setup from the HPM-2002-OBE’s CPU board’s EEPROM into the HPM- 2002-OBE’s CPU.

EER<CR>

HPM-2002-OBEVacuum Gauge

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