HV CAN Isolation Resistance Emulator Card

Description of the High Voltage CAN Isolation Resistance Emulator card for HIL Connect Hardware.

Card Introduction

The HV CAN Isolation Resistance card is designed to offer PT1000 or NTC resistor emulation capability. It relies on a discrete resistor array that achieves the desired resistance by toggling individual resistors through low-resistance relays.

HV CAN Isolation Resistance Emulator card revisions

Table 1. Card revisions
Code Revision Part number
MO 1.0 25244

Hardware Settings

Control of the resistance is done via CAN interface. CAN ID: 0x0 to 0xF is selectable by a rotary switch on the card.

Table 2. Hardware Options
Option Method Possible options
CAN ID selection Via internal or external rotary switch CAN ID set from 0 to 15

CAN Message Layout

In a single CAN Message, two resistor channels can be updated. The list of resistor channels is described in Table 3 with definitions below. An example CAN message is provided in the CAN message example section.

Table 3. CAN Message
Byte Message Start Bit Stop Bit Comment
1 Resistor ID 1 8 Resistor ID (i.e. 1)
2 Resistance MSB 9 16 Most Significant Byte of 16-bit resistance representation
3 Resistance LSB 17 24 Least Significant Byte of 16-bit resistance representation
4 Resistor ID 25 32 Resistor ID (i.e. 2)
5 Resistance MSB 33 40 Most Significant Byte of 16-bit resistance representation
6 Resistance LSB 41 48 Least Significant Byte of 16-bit resistance representation
Resistor ID

Resistor IDs are ordinal numbers of resistance channels. For the Isolation Resistance card, Byte 1 must be 1, while Byte 4 must be 2.

Resistance Values

Byte 2 is the Most significant Byte of the resistance 16-bit value of the resistor with ID1.

Byte 3 is the Least significant Byte of the resistance 16-bit value of the resistor with ID1.

Byte 2 is the Most significant Byte of the resistance 16-bit value of the resistor with ID2.

Byte 2 is the Least significant Byte of the resistance 16-bit value of the resistor with ID2.

The method for calculating the 16-bit value is the following:

R b i n a r y = R a c t u a l R L S B

R b i n a r y is a binary representation of the resistance value that should be send as a 16-bit message to the resistor emulator. This value takes a range from 0x0000 to 0xFFFF.

R a c t u a l is the actual value of the resistance which we want to emulate. Note that it will be rounded to an integer multiple of the R L S B value.

R L S B is the least significant bit in the binary weighted network of the resistors soldered to the emulation card. For this card, this is 1 kΩ.

CAN Message example

Channels to be set: 1 and 2 with values 15655900 Ω and 1000000 Ω respectively

R b i n a r y 1 = R a c t u a l 3 R L S B   = 15655900 1000 = 15655.9   r e a l = 15656   [ i n t e g e r ]

R b i n a r y 2 = R a c t u a l 4 R L S B   = 1000000 1000 = 1000   r e a l = 1000   [ i n t e g e r ]

Table 4. Example CAN Message
Byte 1 2 3 4 5 6
Message RES1 MSB1 LSB1 RES2 MSB2 LSB2
Data 0X01 0X03D 0X28 0X02 0X03 0XE8

Hardware Specification

Table 5. Hardware Specification
Parameter Value
Type Resistor emulator
Number of channels 2
Input signal range CAN message
Output range 0..65535000 Ω
Resolution 1000 Ω
Accuracy ±1% ±1.2 Ω
Isolation 1000 V
Update rate 5 ms
Maximum Power 0.50 W
Comment Isolation: Channel to chassis and channel to channel

Connector Data

Table 6. Connector Data
Type Mating part

FCR7350R - S16N-PC Red

6727-2

Pinout

Table 7. Pinout
Connector Pin Resistor channel Comment
X1 n/a R1_1 Terminal 1 of resistor 1
X2 n/a R1_2 Terminal 2 of resistor 1
X3 n/a R2_1 Terminal 1 of resistor 2
X4 n/a R2_2 Terminal 2 of resistor 2