NI-9478 Vendor Configuration Extensions

The following table lists the vendor configuration extensions for the NI-9478.

Table 116. NI-9478 Vendor Configuration Extensions
Index Sub Type R/W Description
0x2001 0 U32 R/W Current Limit Select
0x2002 1 U32 R Error Status A, sent as 16-bit PDO
2 U32 R Error Status B, sent as 16-bit PDO
0x2003 1 U32 R Error Overtemp, sent as 8-bit PDO
0x2004 1 U8 R/W Limit A
2 U8 R/W Limit B
0x2005 0 U8 R/W Refresh Period

Current Limits and Selection

Each of the 15 channels has 2 bits represented in index 0x2001 Current Limit Select, with channel 0 controlled by bits 0 and 1.

NI-9478 Direction Control

Table 117. NI-9478 Scan List Format
Bits Field
31..30

0: Limit A

1: Limit B

2: No Limit

3: (no charge)

29..28
...
1..0

The current limits are set in index 0x2002 sub-indices1 (Limit A) and 2 (Limit B). The current limits are 8-bit unsigned integers in increments of 20 mA (1 = 20 mA, 2 = 40 mA, and so on).

Error Status and Overtemp

The two error status fields each hold 16 bits of data (one bit per channel, with bit 0 for channel 0). The error status bits in 0x2002.1 are for Limit A reporting. Bits 0x2002.2 are for Limit B reporting.

Errors are reported for at least one cycle and are automatically cleared by the module when appropriate.

The Error Overtemperature field has seven bits to ignore and one bit (bit 0) that when set indicates that the module in an over-temperature condition.

Bits Field
7..1 Reserved
0 Overtemp

Refresh Period

During the Refresh Period, output values that may have experienced an over-current condition are re-enabled. An eight byte value in 10 μs is listed in the following table.

Value Description
0 Infinity (no refresh)
1 Invalid value
2..255 20 μs to 2,550 μs refresh period